-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Type-safe, non-relational, multi-backend persistence.
--   
--   This library provides just the general interface and helper functions.
--   You must use a specific backend in order to make this useful.
@package persistent
@version 0.6.3

module Database.Persist.TH.Library
apE :: Either x (y -> z) -> Either x y -> Either x z

module Database.Persist.Util
nullable :: [String] -> Bool
deprecate :: String -> a -> a


-- | API for database actions. The API deals with fields and entities. In
--   SQL, a field corresponds to a column, and should be a single
--   non-composite value. An entity corresponds to a SQL table, so an
--   entity is a collection of fields.
module Database.Persist.Base

-- | A raw value which can be stored in any backend and can be marshalled
--   to and from a <a>PersistField</a>.
data PersistValue
PersistText :: Text -> PersistValue
PersistByteString :: ByteString -> PersistValue
PersistInt64 :: Int64 -> PersistValue
PersistDouble :: Double -> PersistValue
PersistBool :: Bool -> PersistValue
PersistDay :: Day -> PersistValue
PersistTimeOfDay :: TimeOfDay -> PersistValue
PersistUTCTime :: UTCTime -> PersistValue
PersistNull :: PersistValue
PersistList :: [PersistValue] -> PersistValue
PersistMap :: [(Text, PersistValue)] -> PersistValue

-- | intended especially for MongoDB backend
PersistObjectId :: ByteString -> PersistValue

-- | A SQL data type. Naming attempts to reflect the underlying Haskell
--   datatypes, eg SqlString instead of SqlVarchar. Different SQL databases
--   may have different translations for these types.
data SqlType
SqlString :: SqlType
SqlInt32 :: SqlType

-- | FIXME 8-byte integer; should be renamed SqlInt64
SqlInteger :: SqlType
SqlReal :: SqlType
SqlBool :: SqlType
SqlDay :: SqlType
SqlTime :: SqlType
SqlDayTime :: SqlType
SqlBlob :: SqlType

-- | A value which can be marshalled to and from a <a>PersistValue</a>.
class PersistField a
toPersistValue :: PersistField a => a -> PersistValue
fromPersistValue :: PersistField a => PersistValue -> Either String a
sqlType :: PersistField a => a -> SqlType
isNullable :: PersistField a => a -> Bool

-- | A single database entity. For example, if writing a blog application,
--   a blog entry would be an entry, containing fields such as title and
--   content.
class PersistEntity val where { data family EntityField val :: * -> *; data family Unique val :: ((* -> *) -> * -> *) -> *; }
persistColumnDef :: PersistEntity val => EntityField val typ -> ColumnDef
entityDef :: PersistEntity val => val -> EntityDef
toPersistFields :: PersistEntity val => val -> [SomePersistField]
fromPersistValues :: PersistEntity val => [PersistValue] -> Either String val
halfDefined :: PersistEntity val => val
persistUniqueToFieldNames :: PersistEntity val => Unique val backend -> [String]
persistUniqueToValues :: PersistEntity val => Unique val backend -> [PersistValue]
persistUniqueKeys :: PersistEntity val => val -> [Unique val backend]
class (MonadIO (b m), MonadIO m, Monad (b m), Monad m) => PersistBackend b m
insert :: (PersistBackend b m, PersistEntity val) => val -> b m (Key b val)
replace :: (PersistBackend b m, PersistEntity val) => Key b val -> val -> b m ()
update :: (PersistBackend b m, PersistEntity val) => Key b val -> [Update val] -> b m ()
updateWhere :: (PersistBackend b m, PersistEntity val) => [Filter val] -> [Update val] -> b m ()
delete :: (PersistBackend b m, PersistEntity val) => Key b val -> b m ()
deleteBy :: (PersistBackend b m, PersistEntity val) => Unique val b -> b m ()
deleteWhere :: (PersistBackend b m, PersistEntity val) => [Filter val] -> b m ()
get :: (PersistBackend b m, PersistEntity val) => Key b val -> b m (Maybe val)
getBy :: (PersistBackend b m, PersistEntity val) => Unique val b -> b m (Maybe (Key b val, val))
selectEnum :: (PersistBackend b m, PersistEntity val) => [Filter val] -> [SelectOpt val] -> Enumerator (Key b val, val) (b m) a
selectFirst :: (PersistBackend b m, PersistEntity val) => [Filter val] -> [SelectOpt val] -> b m (Maybe (Key b val, val))
selectKeys :: (PersistBackend b m, PersistEntity val) => [Filter val] -> Enumerator (Key b val) (b m) a
count :: (PersistBackend b m, PersistEntity val) => [Filter val] -> b m Int
data PersistFilter
Eq :: PersistFilter
Ne :: PersistFilter
Gt :: PersistFilter
Lt :: PersistFilter
Ge :: PersistFilter
Le :: PersistFilter
In :: PersistFilter
NotIn :: PersistFilter
BackendSpecificFilter :: String -> PersistFilter
data PersistUpdate
Assign :: PersistUpdate
Add :: PersistUpdate
Subtract :: PersistUpdate
Multiply :: PersistUpdate
Divide :: PersistUpdate
data SelectOpt v
Asc :: (EntityField v typ) -> SelectOpt v
Desc :: (EntityField v typ) -> SelectOpt v
OffsetBy :: Int -> SelectOpt v
LimitTo :: Int -> SelectOpt v
data SomePersistField
SomePersistField :: a -> SomePersistField

-- | Call <tt>select</tt> but return the result as a list.
selectList :: (PersistEntity val, PersistBackend b m) => [Filter val] -> [SelectOpt val] -> b m [(Key b val, val)]

-- | Insert a value, checking for conflicts with any unique constraints. If
--   a duplicate exists in the database, it is returned as <a>Left</a>.
--   Otherwise, the new <a>Key</a> is returned as <a>Right</a>.
insertBy :: (PersistEntity v, PersistBackend b m) => v -> b m (Either (Key b v, v) (Key b v))

-- | A modification of <a>getBy</a>, which takes the <a>PersistEntity</a>
--   itself instead of a <a>Unique</a> value. Returns a value matching
--   <i>one</i> of the unique keys. This function makes the most sense on
--   entities with a single <a>Unique</a> constructor.
getByValue :: (PersistEntity v, PersistBackend b m) => v -> b m (Maybe (Key b v, v))

-- | Same as get, but for a non-null (not Maybe) foreign key Unsafe unless
--   your database is enforcing that the foreign key is valid
getJust :: (PersistBackend b m, PersistEntity val, Show (Key b val)) => Key b val -> b m val
belongsTo :: (PersistBackend b m, PersistEntity ent1, PersistEntity ent2) => (ent1 -> Maybe (Key b ent2)) -> ent1 -> b m (Maybe ent2)

-- | same as belongsTo, but uses <tt>getJust</tt> and therefore is
--   similarly unsafe
belongsToJust :: (PersistBackend b m, PersistEntity ent1, PersistEntity ent2) => (ent1 -> Key b ent2) -> ent1 -> b m ent2

-- | Check whether there are any conflicts for unique keys with this entity
--   and existing entities in the database.
--   
--   Returns <a>True</a> if the entity would be unique, and could thus
--   safely be <a>insert</a>ed; returns <a>False</a> on a conflict.
checkUnique :: (PersistEntity val, PersistBackend b m) => val -> b m Bool
class PersistEntity a => DeleteCascade a b
deleteCascade :: (DeleteCascade a b, PersistBackend b m) => Key b a -> b m ()
deleteCascadeWhere :: (DeleteCascade a b, PersistBackend b m) => [Filter a] -> b m ()
data PersistException

-- | Generic Exception
PersistError :: String -> PersistException
PersistMarshalError :: String -> PersistException
PersistInvalidField :: String -> PersistException
PersistForeignConstraintUnmet :: String -> PersistException
PersistMongoDBError :: String -> PersistException
PersistMongoDBUnsupported :: String -> PersistException
data Update v
Update :: EntityField v typ -> typ -> PersistUpdate -> Update v
updateField :: Update v -> EntityField v typ
updateValue :: Update v -> typ
updateUpdate :: Update v -> PersistUpdate
updateFieldName :: PersistEntity v => Update v -> String

-- | Filters which are available for <tt>select</tt>, <a>updateWhere</a>
--   and <a>deleteWhere</a>. Each filter constructor specifies the field
--   being filtered on, the type of comparison applied (equals, not equals,
--   etc) and the argument for the comparison.
data Filter v
Filter :: EntityField v typ -> Either typ [typ] -> PersistFilter -> Filter v
filterField :: Filter v -> EntityField v typ
filterValue :: Filter v -> Either typ [typ]
filterFilter :: Filter v -> PersistFilter

-- | convenient for internal use, not needed for the API
FilterAnd :: [Filter v] -> Filter v
FilterOr :: [Filter v] -> Filter v
newtype Key backend entity
Key :: PersistValue -> Key backend entity
unKey :: Key backend entity -> PersistValue
data EntityDef
EntityDef :: String -> [String] -> [ColumnDef] -> [UniqueDef] -> [String] -> EntityDef
entityName :: EntityDef -> String
entityAttribs :: EntityDef -> [String]
entityColumns :: EntityDef -> [ColumnDef]
entityUniques :: EntityDef -> [UniqueDef]
entityDerives :: EntityDef -> [String]
type ColumnName = String
type ColumnType = String
data ColumnDef
ColumnDef :: ColumnName -> ColumnType -> [String] -> ColumnDef
columnName :: ColumnDef -> ColumnName
columnType :: ColumnDef -> ColumnType
columnAttribs :: ColumnDef -> [String]
data UniqueDef
UniqueDef :: String -> [ColumnName] -> UniqueDef
uniqueName :: UniqueDef -> String
uniqueColumns :: UniqueDef -> [ColumnName]
fst3 :: (t, t1, t2) -> t
snd3 :: (t, t1, t2) -> t1
third3 :: (t, t1, t2) -> t2
limitOffsetOrder :: PersistEntity val => [SelectOpt val] -> (Int, Int, [SelectOpt val])

-- | Represents a value containing all the configuration options for a
--   specific backend. This abstraction makes it easier to write code that
--   can easily swap backends.
class PersistConfig c where { type family PersistConfigBackend c :: (* -> *) -> * -> *; type family PersistConfigPool c; }
loadConfig :: PersistConfig c => TextObject -> Either String c
withPool :: (PersistConfig c, Applicative m, MonadControlIO m) => c -> (PersistConfigPool c -> m a) -> m a
runPool :: (PersistConfig c, MonadControlIO m) => c -> PersistConfigBackend c m a -> PersistConfigPool c -> m a
instance Typeable PersistException
instance Typeable PersistValue
instance Typeable SqlType
instance Show PersistException
instance Show PersistValue
instance Read PersistValue
instance Eq PersistValue
instance Ord PersistValue
instance Show SqlType
instance Read SqlType
instance Eq SqlType
instance Show (Key backend entity)
instance Read (Key backend entity)
instance Eq (Key backend entity)
instance Ord (Key backend entity)
instance PersistField (Key backend entity)
instance Show ColumnDef
instance Show UniqueDef
instance Show EntityDef
instance Read PersistFilter
instance Show PersistFilter
instance Read PersistUpdate
instance Show PersistUpdate
instance Enum PersistUpdate
instance Bounded PersistUpdate
instance PersistField PersistValue
instance PersistField SomePersistField
instance PersistField a => PersistField (Maybe a)
instance PersistField UTCTime
instance PersistField TimeOfDay
instance PersistField Day
instance PersistField Bool
instance PersistField Double
instance PersistField Word64
instance PersistField Word32
instance PersistField Word16
instance PersistField Word8
instance PersistField Int64
instance PersistField Int32
instance PersistField Int16
instance PersistField Int8
instance PersistField Int
instance PersistField Html
instance PersistField Text
instance PersistField ByteString
instance PersistField String
instance SinglePiece PersistValue
instance Error PersistException
instance Exception PersistException

module Database.Persist.Quasi

-- | Parses a quasi-quoted syntax into a list of entity definitions.
parse :: String -> [EntityDef]
instance Eq LineType


-- | Code that is only needed for writing GenericSql backends.
module Database.Persist.GenericSql.Internal
data Connection
Connection :: (Text -> IO Statement) -> (RawName -> [RawName] -> Either Text (Text, Text)) -> IORef (Map Text Statement) -> IO () -> (forall v. PersistEntity v => (Text -> IO Statement) -> v -> IO (Either [Text] [(Bool, Text)])) -> ((Text -> IO Statement) -> IO ()) -> ((Text -> IO Statement) -> IO ()) -> ((Text -> IO Statement) -> IO ()) -> (RawName -> String) -> String -> Connection
prepare :: Connection -> Text -> IO Statement
insertSql :: Connection -> RawName -> [RawName] -> Either Text (Text, Text)
stmtMap :: Connection -> IORef (Map Text Statement)
close :: Connection -> IO ()
migrateSql :: Connection -> forall v. PersistEntity v => (Text -> IO Statement) -> v -> IO (Either [Text] [(Bool, Text)])
begin :: Connection -> (Text -> IO Statement) -> IO ()
commitC :: Connection -> (Text -> IO Statement) -> IO ()
rollbackC :: Connection -> (Text -> IO Statement) -> IO ()
escapeName :: Connection -> RawName -> String
noLimit :: Connection -> String
data Statement
Statement :: IO () -> IO () -> ([PersistValue] -> IO ()) -> (forall a m. MonadControlIO m => [PersistValue] -> (RowPopper m -> m a) -> m a) -> Statement
finalize :: Statement -> IO ()
reset :: Statement -> IO ()
execute :: Statement -> [PersistValue] -> IO ()
withStmt :: Statement -> forall a m. MonadControlIO m => [PersistValue] -> (RowPopper m -> m a) -> m a
withSqlConn :: MonadControlIO m => IO Connection -> (Connection -> m a) -> m a
withSqlPool :: MonadControlIO m => IO Connection -> Int -> (Pool Connection -> m a) -> m a
type RowPopper m = m (Maybe [PersistValue])

-- | Create the list of columns for the given entity.
mkColumns :: PersistEntity val => val -> ([Column], [UniqueDef'])
data Column
Column :: RawName -> Bool -> SqlType -> Maybe String -> (Maybe (RawName, RawName)) -> Column
cName :: Column -> RawName
cNull :: Column -> Bool
cType :: Column -> SqlType
cDefault :: Column -> Maybe String
cReference :: Column -> (Maybe (RawName, RawName))
type UniqueDef' = (RawName, [RawName])
refName :: RawName -> RawName -> RawName
tableColumns :: EntityDef -> [(RawName, String, [String])]
rawFieldName :: ColumnDef -> RawName
rawTableName :: EntityDef -> RawName
rawTableIdName :: EntityDef -> RawName
newtype RawName
RawName :: String -> RawName
unRawName :: RawName -> String
filterClause :: PersistEntity val => Bool -> Connection -> [Filter val] -> String
filterClauseNoWhere :: PersistEntity val => Bool -> Connection -> [Filter val] -> String
getFieldName :: EntityDef -> String -> RawName
dummyFromFilts :: [Filter v] -> v
orderClause :: PersistEntity val => Bool -> Connection -> SelectOpt val -> String
getFiltsValues :: PersistEntity val => Connection -> [Filter val] -> [PersistValue]
instance Eq RawName
instance Ord RawName

module Database.Persist.GenericSql.Raw
withStmt :: MonadControlIO m => Text -> [PersistValue] -> (RowPopper (SqlPersist m) -> SqlPersist m a) -> SqlPersist m a
execute :: MonadIO m => Text -> [PersistValue] -> SqlPersist m ()
newtype SqlPersist m a
SqlPersist :: ReaderT Connection m a -> SqlPersist m a
unSqlPersist :: SqlPersist m a -> ReaderT Connection m a
getStmt' :: Connection -> Text -> IO Statement
getStmt :: MonadIO m => Text -> SqlPersist m Statement
instance Monad m => Monad (SqlPersist m)
instance MonadIO m => MonadIO (SqlPersist m)
instance MonadTrans SqlPersist
instance Functor m => Functor (SqlPersist m)
instance Applicative m => Applicative (SqlPersist m)
instance MonadControlIO m => MonadControlIO (SqlPersist m)
instance MonadPlus m => MonadPlus (SqlPersist m)


-- | This is a helper module for creating SQL backends. Regular users do
--   not need to use this module.
module Database.Persist.GenericSql
newtype SqlPersist m a
SqlPersist :: ReaderT Connection m a -> SqlPersist m a
unSqlPersist :: SqlPersist m a -> ReaderT Connection m a
data Connection
type ConnectionPool = Pool Connection
data Statement
runSqlConn :: MonadControlIO m => SqlPersist m a -> Connection -> m a
runSqlPool :: MonadControlIO m => SqlPersist m a -> Pool Connection -> m a
type Migration m = WriterT [Text] (WriterT CautiousMigration m) ()
parseMigration :: Monad m => Migration m -> m (Either [Text] CautiousMigration)
parseMigration' :: Monad m => Migration m -> m (CautiousMigration)
printMigration :: MonadControlIO m => Migration (SqlPersist m) -> SqlPersist m ()
getMigration :: MonadControlIO m => Migration (SqlPersist m) -> SqlPersist m [Sql]
runMigration :: MonadControlIO m => Migration (SqlPersist m) -> SqlPersist m ()

-- | Same as <a>runMigration</a>, but returns a list of the SQL commands
--   executed instead of printing them to stderr.
runMigrationSilent :: MonadControlIO m => Migration (SqlPersist m) -> SqlPersist m [Text]
runMigrationUnsafe :: MonadControlIO m => Migration (SqlPersist m) -> SqlPersist m ()
migrate :: (MonadControlIO m, PersistEntity val) => val -> Migration (SqlPersist m)

-- | Perform a database commit.
commit :: MonadIO m => SqlPersist m ()

-- | Perform a database rollback.
rollback :: MonadIO m => SqlPersist m ()
newtype Key backend entity
Key :: PersistValue -> Key backend entity
unKey :: Key backend entity -> PersistValue
instance MonadControlIO m => PersistBackend SqlPersist m
instance SinglePiece (Key SqlPersist entity)

module Database.Persist.Join
class PersistBackend b m => RunJoin a b m where { type family Result a; }
runJoin :: RunJoin a b m => a -> b m (Result a)
data SelectOneMany backend one many
SelectOneMany :: [Filter one] -> [SelectOpt one] -> [Filter many] -> [SelectOpt many] -> ([Key backend one] -> Filter many) -> (many -> Key backend one) -> Bool -> SelectOneMany backend one many
somFilterOne :: SelectOneMany backend one many -> [Filter one]
somOrderOne :: SelectOneMany backend one many -> [SelectOpt one]
somFilterMany :: SelectOneMany backend one many -> [Filter many]
somOrderMany :: SelectOneMany backend one many -> [SelectOpt many]
somFilterKeys :: SelectOneMany backend one many -> [Key backend one] -> Filter many
somGetKey :: SelectOneMany backend one many -> many -> Key backend one
somIncludeNoMatch :: SelectOneMany backend one many -> Bool
selectOneMany :: ([Key backend one] -> Filter many) -> (many -> Key backend one) -> SelectOneMany backend one many
instance (PersistEntity one, PersistEntity many, Ord (Key backend one), PersistBackend backend monad) => RunJoin (SelectOneMany backend one many) backend monad

module Database.Persist.Join.Sql
class RunJoin a
runJoin :: (RunJoin a, MonadControlIO m) => a -> SqlPersist m (Result a)
instance (PersistEntity one, PersistEntity many, Eq (Key SqlPersist one)) => RunJoin (SelectOneMany SqlPersist one many)

module Database.Persist

-- | A value which can be marshalled to and from a <a>PersistValue</a>.
class PersistField a
toPersistValue :: PersistField a => a -> PersistValue
fromPersistValue :: PersistField a => PersistValue -> Either String a
sqlType :: PersistField a => a -> SqlType
isNullable :: PersistField a => a -> Bool

-- | A single database entity. For example, if writing a blog application,
--   a blog entry would be an entry, containing fields such as title and
--   content.
class PersistEntity val where { data family EntityField val :: * -> *; data family Unique val :: ((* -> *) -> * -> *) -> *; }
persistColumnDef :: PersistEntity val => EntityField val typ -> ColumnDef
entityDef :: PersistEntity val => val -> EntityDef
toPersistFields :: PersistEntity val => val -> [SomePersistField]
fromPersistValues :: PersistEntity val => [PersistValue] -> Either String val
halfDefined :: PersistEntity val => val
persistUniqueToFieldNames :: PersistEntity val => Unique val backend -> [String]
persistUniqueToValues :: PersistEntity val => Unique val backend -> [PersistValue]
persistUniqueKeys :: PersistEntity val => val -> [Unique val backend]
class (MonadIO (b m), MonadIO m, Monad (b m), Monad m) => PersistBackend b m
insert :: (PersistBackend b m, PersistEntity val) => val -> b m (Key b val)
replace :: (PersistBackend b m, PersistEntity val) => Key b val -> val -> b m ()
update :: (PersistBackend b m, PersistEntity val) => Key b val -> [Update val] -> b m ()
updateWhere :: (PersistBackend b m, PersistEntity val) => [Filter val] -> [Update val] -> b m ()
delete :: (PersistBackend b m, PersistEntity val) => Key b val -> b m ()
deleteBy :: (PersistBackend b m, PersistEntity val) => Unique val b -> b m ()
deleteWhere :: (PersistBackend b m, PersistEntity val) => [Filter val] -> b m ()
get :: (PersistBackend b m, PersistEntity val) => Key b val -> b m (Maybe val)
getBy :: (PersistBackend b m, PersistEntity val) => Unique val b -> b m (Maybe (Key b val, val))
selectEnum :: (PersistBackend b m, PersistEntity val) => [Filter val] -> [SelectOpt val] -> Enumerator (Key b val, val) (b m) a
selectFirst :: (PersistBackend b m, PersistEntity val) => [Filter val] -> [SelectOpt val] -> b m (Maybe (Key b val, val))
selectKeys :: (PersistBackend b m, PersistEntity val) => [Filter val] -> Enumerator (Key b val) (b m) a
count :: (PersistBackend b m, PersistEntity val) => [Filter val] -> b m Int
newtype Key backend entity
Key :: PersistValue -> Key backend entity
unKey :: Key backend entity -> PersistValue

-- | Call <tt>select</tt> but return the result as a list.
selectList :: (PersistEntity val, PersistBackend b m) => [Filter val] -> [SelectOpt val] -> b m [(Key b val, val)]

-- | Insert a value, checking for conflicts with any unique constraints. If
--   a duplicate exists in the database, it is returned as <a>Left</a>.
--   Otherwise, the new <a>Key</a> is returned as <a>Right</a>.
insertBy :: (PersistEntity v, PersistBackend b m) => v -> b m (Either (Key b v, v) (Key b v))

-- | Same as get, but for a non-null (not Maybe) foreign key Unsafe unless
--   your database is enforcing that the foreign key is valid
getJust :: (PersistBackend b m, PersistEntity val, Show (Key b val)) => Key b val -> b m val
belongsTo :: (PersistBackend b m, PersistEntity ent1, PersistEntity ent2) => (ent1 -> Maybe (Key b ent2)) -> ent1 -> b m (Maybe ent2)

-- | same as belongsTo, but uses <tt>getJust</tt> and therefore is
--   similarly unsafe
belongsToJust :: (PersistBackend b m, PersistEntity ent1, PersistEntity ent2) => (ent1 -> Key b ent2) -> ent1 -> b m ent2

-- | A modification of <a>getBy</a>, which takes the <a>PersistEntity</a>
--   itself instead of a <a>Unique</a> value. Returns a value matching
--   <i>one</i> of the unique keys. This function makes the most sense on
--   entities with a single <a>Unique</a> constructor.
getByValue :: (PersistEntity v, PersistBackend b m) => v -> b m (Maybe (Key b v, v))

-- | Check whether there are any conflicts for unique keys with this entity
--   and existing entities in the database.
--   
--   Returns <a>True</a> if the entity would be unique, and could thus
--   safely be <a>insert</a>ed; returns <a>False</a> on a conflict.
checkUnique :: (PersistEntity val, PersistBackend b m) => val -> b m Bool
data Update v
Update :: EntityField v typ -> typ -> PersistUpdate -> Update v
updateField :: Update v -> EntityField v typ
updateValue :: Update v -> typ
updateUpdate :: Update v -> PersistUpdate
data SelectOpt v
Asc :: (EntityField v typ) -> SelectOpt v
Desc :: (EntityField v typ) -> SelectOpt v
OffsetBy :: Int -> SelectOpt v
LimitTo :: Int -> SelectOpt v

-- | Filters which are available for <tt>select</tt>, <a>updateWhere</a>
--   and <a>deleteWhere</a>. Each filter constructor specifies the field
--   being filtered on, the type of comparison applied (equals, not equals,
--   etc) and the argument for the comparison.
data Filter v
Filter :: EntityField v typ -> Either typ [typ] -> PersistFilter -> Filter v
filterField :: Filter v -> EntityField v typ
filterValue :: Filter v -> Either typ [typ]
filterFilter :: Filter v -> PersistFilter

-- | convenient for internal use, not needed for the API
FilterAnd :: [Filter v] -> Filter v
FilterOr :: [Filter v] -> Filter v
(=., /=., *=., -=., +=.) :: PersistField typ => EntityField v typ -> typ -> Update v

-- | assign a field a value
--   
--   assign a field by addition (+=)
--   
--   assign a field by subtraction (-=)
--   
--   assign a field by multiplication (*=)
--   
--   assign a field by division (/=)
(==., >=., >., <=., <., !=.) :: PersistField typ => EntityField v typ -> typ -> Filter v
(<-., /<-.) :: PersistField typ => EntityField v typ -> [typ] -> Filter v

-- | In
--   
--   NotIn
(||.) :: [Filter v] -> [Filter v] -> [Filter v]